meant to reply to list...
Acutally, I have a system that only contains eMMC flash that is formatted to hold filesystems of one sort or another, so there is no spare "non-filesystem" flash available for the environment. There is also no other form of NVRAM on the device. These are the reasons I asked about whether the environment could be maintained in file form; I have no need to set/get environment variables from userland.
Where is u-boot stored then? Masked ROM, or a uP core in an FPGA? As I said I have a small brain. You can probably graft a R/W file system into u-boot without too much trouble if you need to.
Matt
u-boot is stored as a file in a FAT32 partition of eMMC flash. TI's OMAP 35xx processors can boot that way (x-loader loaded first, then x-loader loads u-boot).
Maybe I don't understand something about eMMC flash. Can u-boot write/read to/from a raw partition of eMMC, (i.e. not in any sort of file form)? I know u-boot has the ability to read from MMC devices - can it write to them? If so, I'm just not sure how to go about addressing eMMC flash memory in "raw" form. I don't see mmc_read() or mmc_write() immplemented in the u-boot source I have (from TI OMAP 35x SDK, u-boot-1.1.4. Otherwise, how can u-boot support the new class of flash storage including eMMC, eSD, and eLBA?
On the other hand, I see fatload() implemented (which seems to be equivalent to fat_read()); is there a fat_write()? That would solve everything.